We were all excited for Opel to debut the 2017 Insignia during the Paris Motor Show this week, until the German brand didn't.

Courtesy of a small note buried in The Irish Times Paris Motor Show Coverage, we now know Opel will show it's new saloon during the 2017 Geneva Motor Show in March.
Rumours that the new Opel Insignia would be unveiled in Paris prove to be unfounded. The important Opel will debut in Geneva next year.
Opel's delay has a knock on effect for Buick and Holden. The 2017 Insignia will form the basis for both the 2018 Buick Regal and the 2018 Holden Commodore. It was thought we would see Insignia in Paris, opening up the LA or Detroit shows for Buick to show the new Regal.

As it stands now, we're likely to see Buick show off the 2018 Regal during the 2017 New York International Auto Show in April of next year.